<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title>层叠</title>
        <link rel="stylesheet" href="cd.css" type="text/css">
        <style>
            #one{color:green; border:3px solid green;background-color: pink;}
            .one{color:blue;border:3px solid blue;background-color: darkgray;}
            
        </style>
    </head>
    <body>
       <div id="one" class="one" style="color:red;">
            ID为one，Class为one的DIV

       </div>
    </body>
</html>